PACKAGE AND METHOD OF MAKING SAID PACKAGE

Abstract: In a package (1) comprising a liquid impermeable first outer layer of a thermoplastic material being heat sealed to a liquid impermeable seam (2) along at least a part of its periphery, the package material comprises a second layer (4) being arranged adjacent the first layer, said second layer (4) including liquid absorbent material for absorbing liquid which possibly leaks within the closed package, and wherein said heat sealed impermeable seam (2) includes said first as well as said second layer (3, 4).

Description: PACKAGE AND METHOD OF MAKING SAID PACKAGE The present invention concerns a package in accordance with th preamble of claim 1. Packages of this kind are well known and are used for a plurality of applications, e.g. for containing all kinds of foods stuffs and other items which are to be protected from external influence as well as a barrier to protect the environment against the influence from the contained goods. Th latter case may be in respect of infectious or poisonous goods transported as an example to a laboratory for analysis. A package arrangment of the latter kind is known from US-A-4 882 893. In this device a plastic bag (22) with a water impermeable seal is used as moisture barrier against the environment. In addition to this plastic bag, the package arrangement includes a shock absorbing layer, a pressure vesse and a moisture absorbent to minimize the risk for the dangerou substance to leak out into the environment. According to international conventions package arrangements fo dangerous goods must fulfil certain difined requirements with respect i.a. to shock resistance and absorbing capacity. According to the above US-document this is solved by the addition of separate absorbing elements which are placed in a pressure vessel. The cited device thus demands a separate operation for placing absorbing material in the correct amount when it is made ready for use. This of course leads to the ris of the person completing the package forgetting the absorbing material or supplies such material in inadequate amounts. Further it may be disadvantageous to locate absorbing material in a particular place in the package in view of the fact that leaking fluid has to be transported/flow a certain distance to come into contact with the absorbing material. Free liquids in the package is undesired since this would essentially increase the risk of spreading the liquid if the barrier material bursts. Also in packages for other types of goods than dangerous products it is often disadvantageous to place absorbent local within a package, or that a separate absorbing element has to be placed in the package. From US-A-4 927 010 a package with an outer impervious layer, an absorbent panel and an inner permeable layer is previously known. The package is sealed into an impermeable seam in the border area along its perifery, whereby the absorbent panels are not included in the seam. From EP-A2-0 317 047 is further previously known a bag, within which an inner bag of a liquid absorbent material is inserted. The impermeable seam solely comprises the impermeable layer comprising the outer bag. Further, from EP-A2-0 368 007 a package comprising an impervious layer and an absorbent material is previously know wherein however, it is not mentioned that the absorbent material could be part of any impervious seam. The devices according to three last mentioned documents deman particular and complicated methods of production wherefore the become costly and time consuming to produce. It is an aim with this invention to overcome the above proble with respect to safely taking up and absorbing liquids possibl leaking, within an impermeable package, inside said package as close to the place of leakage as possible, to provide a packag which is simple and inexpensive in production and well suited for manufacture in conventional equipment. This and also other aims are achieved by the package of the above kind being characterized by the features according to the characterizing portion of claim 1. By the impermeable seam also including the absorbent layer, it is achieved that the absorbent layer not has to be eliminated from the area forming the seam, which leads to considerable advantages over the prior art. By a suitable choice of materia and thickness of the impermeable layer, as well as choice of sufficiently permeable absorbent layer, the material of the impermeable layer may be brought to penetrate and bind the absorbent layer in the heat sealing operation so as to form a impermeable seam. For this purpose the sealing operation may carried out by known heat sealing methods in conventional hea sealing devices in the same way as when producing a conventional impermeable pouch package, leading to the possibility of far more efficient and costworthy production methods than before. As a further advantage it may be mentione that the absorbent layer hereby is integrated in the package and that the absorbent layer is effectivly controlled due to its fixation in the seam. By said inner layer, according to claim 2, including thermoplastic material distibuted within the layer, said material being heat sealable with said first layer, a considerable advantage is achieved with respect to the production of the package, since more compact and/or thicker and thereby more effective absorbent layers and thinner impermeable layers may be used. By the addition of thermoplastic material in proper amounts distributed in the absorbent layer, an internal melting of the plastic material within that layer is achieved in the heat sealing operation, leading to effective binding of the absorbent which is present in the seam area in such a way that the result will be a seam with very good sealing properties. The presence of thermoplastic material may also have the effec of holding together the absorbent layer. By the features according to claims 3 and 4 advantages particularly with respect to the production of the package are achieved. The features according to claims 5 - 8 concern materials havin proved to be particularly suitable and by the feature accordin to claim 9 a further advantage is achieved with respect to manufacturing, since the absorbent material in itself comprise the heat sealable material. This way the second layer only needs to include one type of material. Additional materials may, however, be present in the same layer or additional layers. By the features according to claims 11 and 12 it is achieved that the second layer is protected from mechanical influence from the contents of the package and/or that the contents of the package is protected from influence from the second layer, e.g. loosening fibres, or, in the case where the absorbent material is in a powder form, escaping powder particles. The feature according to claim 14 states that the first layer is the outside of the package and by the feature according to claim 15 it is achieved that also other layers may be integrated into the package according to desire and need. This way the package may be given properties increasing the resistance against influences of different kinds, or given an attractive appearance to the package, or allows writing onto i etc. The invention also concerns an appropriate method of manufacturing a package, and the features according to the claims 17 - 20 lead to the advantages discussed earlier with respect to the corresponding device claims. Further advantages are achieved by the further claims. The invention will now be described in brief with reference to an embodiment and the enclosed drawing, showing a detail of a sealed, liquid impermeable package according to the invention in a sectional view. In Fig. 1, 1 generally indicates a detail of a package according to the invention. 2 indicates a heat sealed edge area, forming a liquid impermeable seam so that possible liquid within the inside 10 of the package remains within said package. The package material of the embodiment comprises a laminated material with a first outer layer 3 of for example polyethylen or polypropylen. This layer is produced with a thickness which is appropriate for the r esent use. Inside th first layer 3 a second layer 4 is located which in this case laminated to the first layer 3. The second layer 4 includes liquid absorbent material as well as a thermoplastic material evenly distributed within the layer, said thermoplastic material being heat bindable with the material of the first layer 3. This way it is easy to achieve a completely liquid impermeable seam at the seam area 2 by conventional heat sealix. s the material using conventional heat sealing equipment Different technics may be used in the heat sealing procedure. As an example the pressing may be continuous on strip shaped starting material by means of press roller means and direct heat or by applying infra-red heating or ultrasonic heating. I is of course also possible to use intermittent heat sealing means. The heat sealing process is in that case conducted in a way known per see. Inwardly the second layer the package material comprises a third porous layer, having pores of such a reduced size that particles or fibres in the second layer 4 are not able to penetrate into the inside 10 of the package. This layer is of course also heat-bindable with the thermoplastic material of the layer 4 for achieving the impermeable seam 2. The invention is not limited by the above embodiment but only by the definitions of the annexed patent claims. Other materials than these discussed above may come into question, and details, as proportion of materials, thicknesses of layers and absorbent proporties are of course adjusted to the particular use. Concerning the seam area 2, it may be mentioned that the width of the seam of course effects the sealing properties and that one skilled in the art easily may test seam width, material composition, extent of pressing as well as suitable temperature for obtaining a liquid impermeabl seam. It is not excluded that the package comprises more layers, as an example containing different types of absorbent material. In this connection it may be mentioned that a composition of the layer 4 which has been found suitable comprises 15% polyolefin fibres, 20% so called super absorbent in fibre or powder form and 65% cellulose fibres (% by weight) Normally the package according to the invention is comprised o a bag with one open side, which after the packing of the goods may be closed in different ways, whereby mechanical clamping devices of per se known kinds, as clips, tightening strips or the like, or also heat sealing may come into question. In the latter case the heat sealing is conducted principally in the same manner as for the seam 2. The starting material may be formed by an absorbent layer bein flow coated, spread coated or sprayed with the material formin the impermeable layer or by heat laminating of two existing layers. Also other laminating methods are possible. In the cas where also a third layer 5 is involved, the laminating process may be e.g. a heat laminating process. Even if the package according to the invention preferably comprises laminated layers, the invention also covers non laminated layers, provided that all layers are present in the seam. Although the invention has been described with respect to a package where the absorbent layer is present over essentially the entire surfaces, it also ranges the cases where a film of exclusively impermeable plastic material (e.g. polyethylen) is hot sealed into an impervious seam with a laminate according t the above. This way, as an example, one side of the package ma be transparent so that the contained goods may be observed. The absorbent layer may be woven, but it is prefered that it i manufactured in a process for manufacturing non-woven material, which e.g. is carded together. The outer surface of the package may be comprised of said firs layer of a thermoplastic material, resulting in an easily produced and smooth package. Alternatively one or more further layers may be located outside the first layer so as to give certain desired properties to the package. Further layers of paper, textile, metal, plastic etc. may be involved, whereby paper as the most outward layer i.a. makes it possible to writ on the package and gives the package an appearance which is desired in many applications. Textile, metal and further plastic layers may give protection against outside influences of different kinds, as for example tearing, radiation and leakage. Several layers of different materials may come into question.

Claims: C L A I M S 1. Package (1) comprising a liquid impermeable first layer (3) of a thermoplastic material, which is heat sealed into a liqui impermeable seam (2) in an edge area along at least a part of its periphery, whereby, adjacent at least one of the meeting films of the first layer, it also comprises a second layer (4) which includes liquid absorbing material for absorbing liquid which is possibly leaking within the closed package, c h a - r a c t e r i z e d in that said heat sealed impermeable sea (2) includes said first as well as said second layer (3,4). 2. Package according to claim 1, c h a r a c t e r i z e d in that said second layer (4) also comprises a thermoplastic material which is distributed within the layer and which is heat bindable together with said first layer (3) . 3. Package according to claims 1 or 2, c h a r a c t e r i ¬ z e d in that said first and second layers (3,4) are laminate to each other. 4. Package according to any of the claims 1 - 3, c h a r a c t e r i z e d in that essentially the entire package comprises a second layer adjacent the first layer (3) . 5. Package according to any of the previous claims, c h a r a c t e r i z e d in that the thermoplastic material of the first layer (3) essentially is comprised of a polyolefi as polyethylen or polypropylen. 6. Package according to any of the claims 2 - 5, c h a r a c t e r i z e d in that the thermoplastic material of the second layer (4) is in the form of fibres. 7. Package according to any of the claims 2 - 6, c h a r a c t e r i z e d in that the thermoplastic material of the second layer (4) essentially is comprised of a polyolefin as polyethylen or polypropylen. 8. Package according to any of the claims 1 - 7, c h a r a c t e r i z e d in that the absorbing material includes cellulose based material or/and so called super absorbent in fibre and/or powder form. 9. Package according to any of the claims 1 - 7, c h a r a c t e r i z e d in that the absorbing material in itself is comprised of a polyolefin having absorbent properties and being heat bindable with the first layer (3) for obtaining said impermeable seam (2) and that further absorbent and/or thermoplastic material may be present in the package material. 10. Package according to claim 9, c h a r a c t e r i z e d in that said polyolefin is treated with a surface tension reduction agent to obtain absorbent properties. 11. Package according to any of the previous claims, c h a r a c t e r i z e d in that it comprises a third layer (5), being laminated inside said second layer (4), said third layer (5) being liquid permeable and stabilises or protects the second layer (4) or protects the contents of the package from direct contact with the second layer (4) . 12. Package according to claim 11, c h a r a c t e r i z e d in that the third layer (5) consists of a porous thermoplastic material layer with a pore size less than the absorbent material particle/fibre diameter. 13. Package according to any of the previous claims, c h a r a c t e r i z e d in that said second layer (4) is a non-woven or woven fibrous material layer. 14. Package according to any of the claims 1 - 13, c h a r a c t e r i z e d in that said first layer (3) is the outer layer of the package. 15. Package according to any of the claims 1 - 13, c h a r a c t e r i z e d in said fist layer on its outside being laminated to at least one further material layer, said further material layer consisting of paper, textile, metal or plastic. 16. Use of the package according to any of the claims 1 - 15, in a packaging arrangement for liquid containing, e.g. biological substances. 17. Method of manufacturing a liquid impermeable bag-like package (1), wherein a liquid impermeable first layer (3) of a thermoplastic material is heat sealed to an impermeable seam (2) in an edge area, along a portion of the periphery of the package, and wherein a second layer (4) of a liquid absorbent material is arranged adjacent one of the films of the first layer, which are meeting at the seam, c h a r a c t e r i z¬ e d in that the heat sealing operation to obtain said impermeable seam (2) is performed so as to include said first as well as said second layer (3,4). 18. Method according to claim 17, c h a r a c t e r i z e d in that said first layer is laminated to a layer of paper, textile, metal, plastic or the like before said heat sealing operation. 19. Method according to claim 17 or 18, c h a r a c ¬ t e r i z e d in that said second layer is joined to said first layer by laminating or the like. 20. Method according to any of the claims 17 - 19, c h a r a c t e r i z e d in said second layer on its free side being laminated to a third layer (5) , which is liquid permeable and comprises a protecting or stabilizing layer and that the heat sealing operation is performed so as to include also this third layer.

Inventors: GENNOW BO, GENNOW, BO
Applicants: GENNOW BO, NOAX AB, GENNOW, BO
Application year: 1994
Main classification: B65D81
IPC codes: B32B7, B65D75, B65D81